Parabola equation changes wrt directrix and focus positions

Students are given the graph of a y= parabola. They are able to move the focus and directrix while studying the changes in the parabola equation (particularly the x^2 coefficient, "a", which determines the parabola shape). They discover that the distance between the focus and directrix, "m", is inversely proportional to "a" - in particular, it can be proved that a = 1/(4m). Students may also study the sign of "a" as they move the focus above and below the directrix.

 

shellerg

 
Resource Type
Activity
Tags
directrix  exponent  focus  parabola  power-function  sphere 
Target Group (Age)
15 – 18
Language
English (United States)
 
 
GeoGebra version
4.2
Views
1907
Report a problem
 
 
© 2018 International GeoGebra Institute